﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.SqlClient;
using System.Configuration;
using System.Data;

namespace TrainingWorkshop.DAL
{
    /// <summary>
    /// The SqlHelper class is intended to encapsulate
    /// best practise for common uses of SqlClient
    /// </summary>
    public class SQLHelper
    {
        //Database connection strings
        public static readonly string ConnectionStringProjectb = ConfigurationManager.ConnectionStrings["projectbConnection"].ConnectionString;

        public static SqlDataReader ExcuteReader(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
        {
            SqlCommand cmd=new SqlCommand();
            SqlConnection conn= new SqlConnection(connectionString);

             // we use a try/catch here because if the method throws an exception we want to 
            // close the connection throw code, because no datareader will exist, hence the 
            // commandBehaviour.CloseConnection will not work
            try {
                PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
                SqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
                cmd.Parameters.Clear();
                return rdr;
            }
            catch {
                conn.Close();
                throw;
            }
        }

        /// <summary>
        /// Prepare a command for execution
        /// </summary>
        /// <param name="cmd">SqlCommand object</param>
        /// <param name="conn">SqlConnection object</param>
        /// <param name="trans">SqlTransaction object</param>
        /// <param name="cmdType">Cmd type e.g. stored procedure or text</param>
        /// <param name="cmdText">Command text, e.g. Select * from Products</param>
        /// <param name="cmdParms">SqlParameters to use in the command</param>
        private static void PrepareCommand(SqlCommand cmd, SqlConnection conn, SqlTransaction trans, CommandType cmdType, string cmdText, SqlParameter[] cmdParms) {

            if (conn.State != ConnectionState.Open)
                conn.Open();

            cmd.Connection = conn;
            cmd.CommandText = cmdText;

            if (trans != null)
                cmd.Transaction = trans;

            cmd.CommandType = cmdType;

            if (cmdParms != null) {
                foreach (SqlParameter parm in cmdParms)
                    cmd.Parameters.Add(parm);
            }
        }
    }
}
